Study of Spin-isospin Excitation by the (p,n) Reaction in the Energy Rang in E_p=10^* 100MeV

实验是在东北大学回旋加速器和放射性同位素中心进行的，用来自K=110 MeV AVF-回旋加速器的70 MeV质子束流和新的束流摆动系统。实验装置的详细情况见参考文献6。中子能量是用飞行时间技术(TOF)测量的，其中中子是用一个由16个圆盘式探测器组成的探测器阵列探测的，该探测器位于距离靶44.3米的地方。探测器在总灵敏体积中填充25.1升有机液体闪烁体BC501a。探测器的绝对效率由^7Li(p，n)^7Be活化分析得到，误差小于±6%。(p，n)截面的绝对大小误差估计在12%以下。靶材是丰度大于95%的~6Li同位素金属箔。对~6Li(p，n)~6Be反应在E_p=50~80 MeV范围内进行了实验研究。Neutr…的微分截面在剩余核中测量了通向五个态的更多的电子。并与基于DW理论的大空间壳体模型预测结果进行了比较。新观测到的E_x=3 MeV的低激发态被初步指定为2^+，T=1。在E_x=15和25 MeV观察到的两个宽凸起被讨论为ΔL=1巨共振的1^和2^-分量。^&lt；12&gt；C(p，n)^&lt；12&gt；N反应已在E_p=70 MeV下进行了实验研究，其分辨率比迄今报道的要好。计算结果与采用Franey和Love 100 MeV有效相互作用的大空间壳层模型和DW计算结果进行了比较。用高分辨TOF技术观测到了E_p=50，70和80 MeV的~&lt；42&gt；Ca(p，n)^&lt；42&gt；Sc反应。用DWBA理论对壳层模型的计算和分析，分别给出了^&lt；42，44&gt；Sc和^&lt；48&gt；Sc核在7，8和10能级上的自旋宇称分配。从LAS和GT截面得到GT矩阵元素B(GT)。在50-80 MeV能量范围内，得到了中等质量核上(p，n)反应的等向量有效相互作用强度比|J&lt；στ&gt；/J_τ|的能量依赖关系。较少

The experiment was performed at the Cyclotron and Radioisotope Center, Tohoku University, with a 70-MeV proton beam from the K=110MeV AVF-cyclotron and the new beam swinger system^<6)>. The details of the experimental setup have been described Ref.6. Neutron energies were measured by the time-of-flight technique (TOF), where neutrons were detected by a detector array consisting of 16peaces of the disk type detector located at 44.3 m from the target. The detectors were filled with 25.1-liter organic liquid scintillator BC501A in the total sensitive volume. The absolute efficiencies of the detectors were obtained from the ^7Li(p,n) ^7Be activation analyses with an error less than ± 6%. Errors in the absolute magnitude of (p,n) cross sections were estimated to be less than 12%. The target was a metallic foil of ^6Li isotopes with enrichments better than 95%.The experimental study for the ^6Li(p,n)^6Be reaction has carried out at E_p=50^- 80 MeV region. Differential cross sections of neutr … More ons leading to the five states in the residual nucleus were measured. Results have been compared with the large-space shell-model prediction based on DW theory. The newly observed low-lying state at E_x= 3MeV has been tentatively assigned to be 2^+, T=1 one. Two broad bump observed at E_x= 15 and 25MeV were discussed as 1^- and 2^- components of the ΔL=1 giant resonance.Experimental study of the ^<12>C(p,n)^<12>N reaction have been carried out at E_p= 70 MeV with better resolution than those so far reported. Results were compared successfully with the predictions based on large-space shell-model and DW calculations where Franey and Love 100MeV effective interactions were applied. Spin-parity assignments for observed seven transition were consistent with previous report.The ^<42>Ca(p,n)^<42>Sc reaction at E_p = 50, 70 and 80 MeV were observed by the high resolution TOF technique. The shell model calculation and analyses with DWBA theory have provided a set of spin-parity assignment over 7, 8 and 10 levels for ^<42,44>Sc, and ^<48>Sc nuclei, respectively. The GT matrix elements B(GT) were obtainded from the LAS and the GT cross sections. The energy dependence of the ratio of isovector effective interaction strengths |J_<στ>/J_τ| was obtained for the (p,n) reaction on a medium mass nucleus in an energy range between 50 and 80 MeV. Less